JPH01265955A - Living bone affinity member and substitute bone with this member in conjugation - Google Patents

Abstract

PURPOSE:To accomplish strong and long-lasting bond with own bones by furnishing through holes from the own bone conjugate side to the base material conjugate side while increasing the dia. gradually, and allowing the surface on the base material side to be missing partially. CONSTITUTION:Through holes 9 are provided from the own bone conjugate side of a living body bone-affinity member 8 to the base material conjugate side of a substitute bone in such a way as increasing the dia. gradually. The surface of this member 8 on its base material side is left partially missing so as to form a groove 10, and thereby openings at the base material conjugate side are put in mutual communication between one or more adjoining ones. When osteoblasts intrude into these through holes 9 and a new-born bone is formed, it works as if anchor to fix the substitute bone and own bones together firmly.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a biological bone-compatible member that is used by being joined to a bone substitute to compensate for a bone defect in a living body, and a bone substitute to which the member is joined. The substitute bone to which the member has been joined is firmly fixed to the autologous bone over a long period of time.

[Prior Art] When bone damage occurs due to an accident, disease, tooth extraction, etc., it is necessary to fill the bone defect or void with some kind of filling material.

In such cases, transplanting living bone from another individual causes an immune rejection reaction, so methods have been used to collect cancellous autologous bone from the patient's own ribs or hip bones and fill the defect. However, this method requires removal of bone tissue other than the damaged area, which increases the number of surgical sites, causes great pain for the patient, and requires a great deal of labor on the part of the doctor. Moreover, since there are restrictions on the location and amount that can be harvested, it is not always possible to secure enough bone to compensate for the defect, creating the need for substitute bone.

It goes without saying that such bone substitutes have strength commensurate with the replacement site, are harmless to living bodies, are firmly fixed to autologous bone, and must not loosen over long-term use.

For example, artificial hip joint stems are made of stainless steel 14. to ensure stable strength over a long period of time. The hip joint stem is made of a corrosion-resistant metal such as a Co--Cr alloy or a titanium alloy, and the following methods are used to fix such metal hip joint stems to living bones.

(1) Cement fixation method: As shown in FIG.
A is inserted, and the gap between the bone marrow cavity and the supporting portion 1a of the substitute bone 1 is filled with bone cement 7 made of polymethyl methacrylate or the like and fixed.

(2) Cementless fixation method: As shown in Fig. 4(b), the supporting portion 1a of the substitute bone 1 is formed to a thickness that fits tightly into the medullary cavity of the autologous bone 2, and the two are tightly fitted. and fix it mechanically.

However, in method (2) as well as method (1) above, a direct bond between metal and autologous bone is not formed between substitute bone 1 and autologous bone 2, so that a long period of time may elapse. In addition to loosening, method (1) had the problem of adverse effects on living organisms due to polymerization heat of cement and component elution.

In order to solve these problems, research has been conducted to eliminate the cement fixation method and to improve the above-mentioned drawbacks of the cementless fixation method. Examples of such an improvement method include FIG. 5(a) and a sectional view of its surface layer (b), (
c) As shown in (d), metal granules 3 or short fibers 4 are randomly arranged on a part of the surface layer of the substitute bone 1 on the side that is in contact with the autologous bone 2, and then diffusion bonding is performed. ,
Alternatively, a method of thermally spraying the metal 6 to form a porous layer 5 on the surface of the bone substitute 1 (or a method of arranging knitted fabrics, woven fabrics, or non-woven fabrics of metal fibers and diffusion bonding, although not shown) is used. According to these methods, osteoblasts growing from the remaining autologous bone invade into the microscopic voids of the porous layer 5, and the anchoring effect of the new bone allows the autologous bone 2 and substitute bone 1 to be firmly fixed. achieved.

[Problem to be solved by the invention] However, even if a satisfactory porous layer is formed as described above, the reproducibility of the porous shape and porosity is not sufficient, and the functional guarantee is insufficient. there were.

In addition, in order for the new bone generated within the porous to continue to grow and survive, it is necessary to receive nutrients through the circulation of body fluids from the capillaries in the autologous bone marrow and to activate the metabolism associated with this. However, since most of the pores obtained as described above are composed of individual, independent pores, the body fluids reach a dead end, and the body fluids cannot be replenished smoothly. Therefore, even if new bone is formed, it will become necrotic and the joint strength of that part will decrease.

Therefore, in the present invention, we investigated a technique that allows the bone substitute and autologous bone to continue to be firmly fixed over a long period of time, and to form a uniform porous layer on the bone substitute with good reproducibility.

[Means for Solving the Problems] The present invention that has solved the above-mentioned problems is a biological bone-compatible member that is joined to the surface of a base material of a substitute bone, and includes a member that is bonded to the base material surface from the autologous bone joint side to the base material joint side. By providing a through-hole that penetrates in a gradually expanding shape toward the compatibility member and by removing a part of the surface of the compatibility member on the base material side, the openings appearing on the base material joining side are connected to each other.
The gist of the structure is that the adjacent openings are communicated with each other, and the substitute bone to which the member is joined is firmly fixed to the autologous bone for a long period of time.

[Function] The biological bone compatible member in the present invention is the symbol 8 in FIG.
As shown in FIG. 2, it is bonded to the surface of the base material of substitute bone 1 and applied to the defective part of autologous bone 2. For example, the partially cutaway perspective view shown in FIG. 2 and FIGS. 3(a) and 3(b) , (c
) and its sectional view taken along line A-A, B-B
As can be seen from the cross-sectional view taken along the line, a through hole 9 is provided that penetrates the biological bone-compatible member in a manner that gradually expands from the autologous bone joining side to the substitute bone base material joining side, and By cutting out a portion and providing the missing groove 10, the structure is such that the openings appearing on the base material bonding side are communicated with one or more adjacent openings.

As described above, if a through hole is provided in the biological bone compatible member that gradually expands toward the side where the substitute bone base material is bonded, when osteoblasts invade the through hole and new bone is formed. Second, the new bone acts like an anchor to firmly fix the substitute bone and the autologous bone.

There are no restrictions on the cross-sectional shape of the through-hole according to the present invention, and it can be any shape as long as it has a portion that gradually expands from the autogenous bone joining side to the substitute bone base material side and does not adversely affect the exertion of the anchor effect. Included in the present invention. However, this alone is not sufficient as a bone substitute, and in order for the new bone to grow and continue to live, nutrition and metabolism are required through fluid circulation from the capillaries in the bone marrow of the autologous bone. Since they communicate on the bone base material joining side, body fluids circulate smoothly and the new bone does not become necrotic, allowing the new bone to continue to grow and maintain excellent strength. Note that this communication must be made at least on the side where the substitute bone base material is joined, and only with this configuration can fluid circulation be ensured at the leading edge of new bone growth.

In order for new bone to invade the porous portion of the living bone compatible member 8 and grow further, the area porosity (opening ratio) of the autogenous bone joining side surface of the member is also important. The volumetric porosity occupied by the through holes 9 and the missing grooves 10 is also important. Although the present invention does not specify the volumetric porosity, it is generally preferable to set it to 50 to 80%. This is because biological metal materials are mainly used as general-purpose materials constituting biological bone-compatible components, and there is no significant difference in material strength except for precious metals such as gold and silver, so the strength of biological metal materials and the strength of new bone are This is because the volume porosity is generally balanced within a range of 50 to 80%. That is, if we consider a state in which new bone has invaded and grown into the cavity of the living body bone compatible member, a composite structure consisting of the material constituting the living body bone compatible member and new bone tissue has been formed. If a load is applied to the bone substitute in this state, it is extremely important to maintain a balance of strength between the living bone-compatible component and the new bone in order to prevent fracture and separation in this area. have meaning.

Materials for biological bone-compatible parts include precious metals such as gold and silver, and 5U.
Examples include stainless steel such as S316, titanium alloys such as Ti-6A l-4V, corrosion-resistant metals such as Co-V alloys, and high-strength ceramics such as alumina, zirconia, and silicon nitride. However, if both are metal materials, it is preferable to use different materials within a range that does not cause potential difference corrosion. Most preferably, the same type of material is used, for example, if the substitute bone base material is Ti-6AI-4V, the biological bone compatible member is also Ti-6.
It is better to use AL-4V.

The frontage size of the autogenous bone joining side surface of the living bone compatible member is 10
0 to 500 μm, preferably 200 to 500 μm, and most preferably around 400 μm. Opening size is 100
If it is less than 500 μm, the invasion of capillaries from osteoblasts and autologous promyelinum will be insufficient, and if it exceeds 500 μm, it will take time to form new bone by osteoblast invasion, and the anchoring effect of new bone will be insufficient. It will be enough.

At this time, if the autologous bone contact side surface of the living body bone-friendly component is roughened by a method such as shot blasting, new bone formation will proceed more quickly and bonding with the autologous bone will occur more quickly than if the surface remains smooth. It also increases.

The width of the missing groove is preferably 100 to 800 μm. 1
00. If it is less than 800 μm, body fluid circulation will be insufficient.
This is because if it exceeds this, there is a risk that the strength of the biological bone-compatible member itself will decrease.

There are no particular restrictions on the manufacturing method of the biological bone-compatible member having the above structure, and depending on the manufacturing method, it is possible to obtain a material with a unique porous structure and appearance. It is sufficient that the through-hole communicates arbitrarily with the opening on the base material side, and to explain the means for manufacturing the one illustrated in FIG. An advantageous method is to provide a through-hole by cutting out a portion from the surface layer on the side of the substitute bone base material to provide a groove, thereby allowing the through-hole to communicate with each other.

If the biological bone-friendly member obtained in this way is bonded to the surface of a substitute bone base material, it can be used to improve the hip joint and knee.

It can be used as a long-term stable substitute bone for joints such as elbows, shoulders, fingers, other long bones, and artificial tooth roots. There are no particular restrictions on the position, shape, size, attachment means, etc. of the mounting surface of the biological bone compatible member on the substitute bone.

[Example] An example according to the present invention will be described with reference to FIGS. 1.2 and 3.

In manufacturing the biological bone compatible member 8 to be joined to the base material surface of the substitute bone 1, Ti-6AI-4 with a thickness of 0.11 mm was used.
One surface of the V plate (the side surface in contact with the autologous bone) was roughened by shot blasting, and a through hole 9 was formed in a gradually expanding manner by electrical discharge machining. The specifications of this through hole were as follows: the opening diameter on the roughened surface was 400 μm, the numerical aperture was 176/cI112, and the diameter on the other side (substitute bone base material side) was 8001.1 m. A groove 10 with a width of 0.4 mm was provided by electric discharge machining, running vertically and horizontally along the surface from the side of the substitute bone substrate to the depth of the board thickness.

The volumetric porosity of the biological bone-compatible member thus obtained was approximately 67%, and the area opening ratio at the side surface in contact with autologous bone was approximately 22%. In addition, the member is bonded to a substitute bone base material (the hip joint stem 1 and the acetabular cup 1 in Fig. 1).
゛) was created.

The opening area at the outermost surface of each through hole 9 is 0.12 mm.
2. The longitudinal cross-sectional area Aa of the axial center of the weakest part in the biological bone affinity member layer was 0.126 mm2. On the other hand, the shear strength of adult bones is generally about 20 kg/cm'', and the fatigue strength of the metal material constituting the biological bone-compatible member of this example is about 2.
Since it is 0 kg/cm2, a good balance is maintained between the strength of the new bone generated in the porous part and the strength of the metal in the porous part.

[Effects of the Invention] Since the present invention is configured as described above, when a bone substitute to which the biological bone-compatible member of the present invention is attached is applied to an autologous bone defect, the member gradually moves toward the substitute bone base material side. The new bone that grows into the enlarged through hole acts like an anchor and firmly fixes the substitute bone and autologous bone. Moreover, since the through holes are in communication, body fluid circulation is ensured, the generated bone continues to grow or survive without necrosis, and the strength of the new bone is maintained.

Furthermore, since the biological bone compatible member can be formed in advance by a mechanical method, a porous layer can be uniformly provided on the substitute bone with good reproducibility.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing an example in which a bone substitute to which the bone-compatible member according to the present invention is bonded is applied to autologous bone, Fig. 2 is a partially cutaway perspective view of the bio-bone-compatible member, and Fig. 3 (a) is A plan view of the biological bone compatible member, FIG. 3(b) is a sectional view taken along line A-A in FIG. 3(a), and FIG. 3(C) is a cross-sectional view taken along line B-- in FIG. 3(a).
B-line arrow sectional view, Figures 4 (a), (b) and 5
Figure (a) shows a common example of conventional bone substitutes, Figure 5 (b)
), (c), and (d) are cross-sectional views of the surface layer portion of FIG. 5(a). 1...Substitute bone 2...Autologous bone 3...Grain 4...Fiber 5...Porous layer
6...Sprayed metal 7...Bone cement 8.
・・Biological bone compatible member 9・Through hole 10・
... Missing groove Fig. 2 Fig. 3 (a) A-A line arrow cross section) B-B line arrow has been updated [B1 4th section a) Fig. 5

Claims (2)

[Claims] (1) A biological bone-compatible member to be joined to the surface of a base material of a bone substitute, which is provided with a through hole that penetrates in a gradual manner from the autologous bone joint side to the base material joint side, and the base of the bone-compatible member A biological bone-compatible member characterized in that openings appearing on the base material joining side are communicated with each other by cutting out a part of the material side surface, and at least one or more adjacent openings communicate with each other. (2) Claims (
1) A substitute bone to which the biological bone-friendly member is attached.